The proposed K02 Independent Scientist Award application to the National Institute on Drug Abuse (NIDA) is an extension of my ongoing commitment to research aiming to address HIV/AIDS stigma among Latino populations, specifically Puerto Ricans. Puerto Rico is a Caribbean Island linked to the United States, where HIV infection prevalence has been estimated at 1% (more than 35,000 reported cases). The Island's epidemic is mainly driven by unclean needle sharing for injected drug use (IDU) and is embedded in the Caribbean region which has the second highest rates of HIV/AIDS in the world. Therefore, the need for stigma- free health services is ever-growing. My research career has been characterized by an ongoing commitment to addressing the role of stigmatization on access to quality health services for people with HIV/AIDS (PWHA) in this setting. In my previous NIH funded studies I have focused on the identification and reduction of HIV/AIDS stigma attitudes among health professionals. The proposed K02 will allow me to extend this research agenda to address the behavioral components of HIV/AIDS stigma as manifested in clinical interactions. My long-term career goals include: 1) advancing the understanding of the interrelation between HIV/AIDS stigma attitudes and behaviors (i.e. verbal and non-verbal) manifested by health professionals in Puerto Rico, 2) documenting the underlying predictors and cultural correlates of HIV/AIDS stigma attitudes and behaviors in the Puerto Rican setting, and 3) developing scientifically tested stigma measurement guidelines and interventions to reduce both HIV/AIDS stigma attitudes and behaviors among this population. As part of the proposed K02 application I propose several career development strategies to foster my long-term career goals. These include: 1) the acquisition of new skills related to the use of Standardized Patient Simulation Technology for use in research via extended contact with the University of Puerto Rico's Standardized Patient Program, and 2) collaborations with experts in the field of visual methodologies and observational data analysis at the University of Rochester, Florida International University and the University of California at San Francisco. With the skills acquired through these interactions, I will be better positioned to implement the proposed research plan in which I propose to study the dynamics of physician/patient interaction that may contribute to stigmatization of PWHA, through an observational study of simulated interactions using a standardized patient (SP) program in Puerto Rico. The proposed study has the following aims: Aim 1 - To document HIV/AIDS stigma attitudes and their role on behavioral manifestations of stigma during physician/patient interactions in a sample of medical residents in Puerto Rico; Aim 2 - To document variations of HIV/AIDS stigma behaviors during physician/patient interactions when providing services to clients with different modes of HIV transmission; and Aim 3 - To determine the role of cultural factors (i.e., traditional gender roles religiosity, homophobia, and stigmatization of drug users) on attitudinal and behavioral manifestations of HIV/AIDS stigma among medical residents in Puerto Rico. To achieve these aims I propose an experimental design using mixed method techniques (structured observations, quantitative questionnaires, and SP simulations). The study will be conducted through the SP program at the University of Puerto Rico's Medical Sciences Campus. I will recruit a sample of 154 medical residents in Puerto Rico to participate in an experiment embedded within their ongoing SP training, and assign them to engage in all of the following patient conditions, with randomized order of presentation: 1) HIV-infected through intravenous drug use, 2) HIV-infected through unprotected heterosexual relations, 3) HIV-infected through unprotected homosexual relations, 4) HIV-infected through unprotected heterosexual relations or intravenous drug use, 5) HIV-infected through unprotected homosexual relations or intravenous drug use, 6) HIV-infected through unprotected homosexual or heterosexual relations, and 7) the common cold as a stigma- free comparison control. Interactions will be video-recorded and subsequently coded for behavioral expressions of stigma using a preliminary developed and pilot-tested measure from my NIH funded studies. After participation in the simulation, all participants will complete quantitative questionnaires addressing HIV/AIDS stigma attitudes and adherence to cultural factors of importance in the Puerto Rican setting. The study will be the first to document behavioral manifestations of HIV/AIDS stigma among medical residents in Puerto Rico, thereby extending the scientific literature that has focused almost exclusively on their stigmatizing attitudes. Furthermore, it will be the first study to address the role of cultural factors on the manifestations of HIV/AIDS stigma among this population in Puerto Rico and variations related to means of infection. The findings from the study have the potential to inform the development of guidelines for stigma measurement and stigma reduction interventions for this population, taking into consideration both attitudinal and behavioral manifestations of stigma, and the role of local culture on these indicators.